Method of making insulators.



' JOHN s. LAPP,

= UNITED sm'ras PATENT or" vIcro New YoRK, AssrenoR To LOCKE msULAroR MFG. j VICTOR, NEW YoRK, A CORPORATION or NEW YoRK.

' ivrnrnon OF MAKING Insum'roRs.

To all whom it may concern:

Be it known that I,

tor, in the county of Ontario and State of New York, have invented certain new and useful Improvements in Methods of Making Insulators; and I do hereby declare the'following to be a full, clear, and exact description of the same, reference being had to the accompanying drawings, forming a part of this. specification, and to the referencenumerals marked thereon. r

- My present invention has for lts object to provide an improved method of manufacturing lnsulators, particularly of the suspension :type adapted'to support high ten-, sion or breakage that is largely due to strains. and

stresses set up by changes in temperatures to which insulators are subjected are very largely obviated.

In the commontype of strain insulator in i which a number of insulating units are connected; these units are generally composed of a central vitreous section usually of porcelain, embodying a hollow hub and a flange or apron, a metallic cap embracing'the exterior of; thehub and a'm'etallic eye'bolt or pin inserted-in the socket of the hub, allthe parts being secured inposition by hydraulic cement between-them. As thus constructed thecylindric'al porcelain hub is interposed between the'hollow; metallic cap and the central pin'or bolt'with relatively thin layers of cement between the parts, and as the coefficient ofexpansion of the pin, usually composed of "drop forged open hearth steel, is practically double that of the porcelain,

" the changes in temperature to which the insul'ators are subjecte'd in use, frequently causes the expansion of the metal elements to crack the porcelain or the vitreous ele- 'rnent,-'Particularly is thiscracking liable to' happen ifthe porcelain or other vitreous material is improp'erly treated during its baking .in the kiln, as under some circum-f stances the particles of the porcelain are under tension, so that a slight chip or crack will cause them to fly to pieces very readily,

somewhat after? the, manner of the well known Prince Rupert drops .As insulators in use are, in many instances, subj ected to extreme variations in' temperature, from say 30 degrees below zero Fah. in winter to 115 to 120 degrees Fah. in midsummer,

the liability of breakage due to variations in Specification of Letters Patent. Application filed January 2, 1914. Serial No. 810,069.

high voltage conductors whereby the 7 Patented'Feb. 1, 1916.

temperature, causing contraction and ex- JOHN S. LAPP, of V1cpansion, is very great. Even if both parts of the insulator are composed of porcelain or' other vitreous material united by cement they are liable to become broken orthe cement joint impaired byunequ al expansion and contraction.

After considerable experimenting I have discovered that, if the hydraulic cement se' curlng the partsis allowed to set when the parts are subjected to a temperature approximating the high temperature which .they areliable to encounter in use, and preferably ina moist atmosphere, the breakage of the porcelain and impairment. of the cement jo nt due to changes in temperature in use, is materially reduced, and particu In the -drawing: The figure 1s a sectional view of .one section of a strain insulator to the manufacture of which my invention is particularly adapted. 1

In the form shown the porcelain or vitreous section of the. insulator embodies a hub portion and the flange B, the latter preferably provided on its underside with. the annular ribs C. I The interior of the hub A is corrugated or roughened as at c and the exterior is provided with the annular ribs '5.

D indicates the pin or eye bolt extending within the hub, preferably formed of a steel extending at about the same angle, and re duced at its lower edge to a less diameter than the top of the shoulder e. A

9a drop forgingphavingthe annular flange d about 3/64. of an inch smaller than the diameter'of the recess in the hub, and above E represents the malleable iron'ca-p adapt ed to receive the exterior of the hub A and of a slightly greater diameter internally than the latter, the inside of this cap being provided with, annular ribs 9 between which and the exterior of the hub is locatedv a filling of hydraulic cement-k. A filling of cement '7' is also arranged between the -interio r of the hub and theexterior of the pin 5 or eye bolt D. The preferred manner of uniting the insulatorsections is as follows: The vitreous or porcelain section is inverted and the hub V extending downwardly and within the hub is placed a quantity of hydraulic cement preferably neat. Portland cement, mixed with'about 30 per cent. by weight ofwater.

The eye bolt or pin is then inserted so that its end is substantially in contact with the lower portion-of the recess in the hub," and it is centered and held for a few .moments to prevent tilting, and then the porcelain and pin are placed in a closet or receptacle which is filled with moists'team at a temperature above that of the atmosphere, and

maintained at approximately this temperature for a number of hours suflicient for the thorough setting of the cement, In'a short v timeafter being placedin the closet'or re ceptacle, the pinand porcelain reach the temperature of the steam, and have attained their maximum degree of expansion and while in this condition the cement is al- -lowed toset. By subjecting the parts and .cement to the action of the heated moistatmosp'here, and also to the action of such steam as may have been condensed, for a considerable period, the cement setsm'ore thoroughly while the parts are expanded I than would be: the case if .subjectedto dry -heat, andthere is practically no tendency for the cement to crumble; The temperature of the steam determines to some 'ex- .tent the time required for proper treatment 40 of the parts as, 'if the temperature is relatively low, say from 115 to 120 degrees Fahrenheit, the parts shouldremain in treatment for from forty-eight -to sixty hours,

I while at-higher temperatures, say 180 degrees, the same results would be accomplished in fr om thirtyto thirty-six hours, but a temperature very much higher'thagi this would render the cement brittle. From,

this it will be'seen that the temperature is 0 more or less a direct measure of the rapidity of the setting of the cement but no exact data can begiven as the character of the cement and other conditions may vary, but the best results are attained between 11 5 to 180 degrees at periods varying from thirty to hours. J After the cement has thoroughly set, the porcelain sections containing the pins are removed from the receptacle,

the iron capsfare' partly filled with cement v sulators composed, ofmeta lie and yitreous-" z f 0 of substantially the same consistency as before, and the hubs placed in them. The section is then returned to the steam closet and this cementallowed to set under subv stantially the same conditions as before, and after therequired period it is removed and "idrauliocement between the parts and suballowed to cool gradually. Even though the temperature of the atmosphere in which the insulators are used may not be greater than 115 degrees Fahrenheit, still as a mat-' ter of fact'the temperature of the insulator itself when exposed to the direct rays of the sun will be considerably higher than this, -but. the expansion of the parts at higher temperatures is relatively slight, so that the range between 115 and 180 degrees is sufiicientto expand the parts during the setting of the cement, andat the same time supply sullici'ent moisture to obtain the best results. .1 v I In addition to the advantages gained by allowinghydraulic cement to set in a moist atmosphere at a relativelyhigh temperature this method also provides ameans of detecting any imperfections in the-galvanized coating that is usually applied to the pins and the caps, to protect them'from corrounsuitable;

While the invention is particularly adapted for the manufacture of insulators in which the parts are united by hydraulic cement some of the advantages are obtained when other cements are employed which become hard at a temperature below their melting point and even with these the feature of holding the parts at a relatively high temperature so thatthey are expanded before the cement hardens, prevents damage to'the insulatorsunder normal working conditions.

I claim as my invention: l. 'The method of uniting the parts ofin; sulators consisting in placing hydraulic-cea merit between the parts and maintaining the. parts at a relatively high temperature. until the cement has set.

2. The method of uniting the parts of insulators consisting in placing liquid hyjectiri'g them and thecement to moisture and 1 a relatively high temperature until 'the cement has set. 3 f

3. The method of uniting the parts of insulators composed of metallic and-vitreous I sections with cement betweenthem, consist-' ing in expanding and holdin the parts ex panded by the application of heatwhile the cement connecting them is setting.

4.; The method of unitin the parts of 5. The method of the parts of insulators composed of metallic and vitreous sections, consisting, in placing liquid bydra-ulic cement betweent'he pants andshh-f jecting them and the cement to heat and moisture until thecement has set.

1 ..6. The method of uniting the parts of ini -".sulators composed of metallic and vitreous sections one surroundingithe other, consisting in placing liquid. hydraulic cement-betweenthe parts and subjecting them andv the .cement to the action of moist steam until the v. cement has, set- I I sulators composed of sections having dif-,

" liquid hydraulic cement between the sections and subjecting the parts. to a relatively high 7 The method joi unitingthe parts of inferent coeflicients of expansion one surrounding the other, Which-consists in placing temperature until" the cement has set.

8. The method of making insulators 'composedof separate sections having different 1 coeflicients ofe'xpansion one surrounding the other, consisting'in placing liquid hydraulic cement-between the parts and subjecting the parts and the'cement to .'moisture and to a relatively-high temperature until thecement v has set, Y

9. The method of making insulators coniposed of separate sections'having diflerent coefficients of expansion one surrounding the other, consisting in placing liquidvhydraulic cement between the par-ts and subjecting them to steam at a relatively high tempera- ;ture until the cement has set.

10. The method of making insulators embodying, a metallic cap and a vitreous sectionhaving a hub entering the cap, consisting in placing liquid hydraulic cement between the interior of the cap and-the exterior of the hub and subjecting the parts and the cement to theaction of moist steam-until thecement has set. a

11. The methodof making'insulators bodying a metallic cap, a vitreous section having a hollow hub ,entering the cap and a'metallic pin extending into the hub, conv sisting in placing'liquid hydraulic cement between the pin and the interior of; the hub,

subjecting the parts and cement to moist steam until the cement sets, then placing liquid hydrauliccemeiit between the cap and the exterior of the hub vandsubjecting the, parts and cement to the action ofmoist Steam until thecement sets.

v v JOHNS. LAPP.

Witnesses a R. V. BALDWIN, K. M. RILEY. 

